GEOCHEMISTRY
cod. 23630

Academic year 2020/21
2° year of course - First semester
Professor
- Lorenzo TOSCANI
Academic discipline
Geochimica e vulcanologia (GEO/08)
Field
Ambito mineralogico-petrografico-geochimico
Type of training activity
Characterising
72 hours
of face-to-face activities
9 credits
hub: PARMA
course unit
in ITALIAN

Learning objectives

The student will have to: 1- learn and be able to use the basic principles of thermodynamics, 2- learn the ability to describe natural processes on the basis of objective characters and learn the methods of representation through the laws referred to in point 1, 3 - develop autonomy in applying the skills learned

Prerequisites

Knowledge learned in the courses of Mathematics, Chemistry and Mineralogy

Course unit content

The contents of the course are represented by 1- introduction to Thermodynamics and its basic principles necessary to understand the other contents of the course, 2- description of low temperature systems, 3- description of high temperature systems using the behavior of the trace elements, 4- use of trace elements for the classification of igneous rocks and for the evaluation of magmatic evolution. 5- Isotopic geochemistry subdivided into radioactive a-isotopes and dating methods of rocks, stable b-isotopes and their applications in climatic and environmental studies.

Full programme

Thermodynamics: intensive and extensive properties, system, phase, component. State functions, the chemical potential, the equilibrium constant.
Low temperature systems
- Equilibria in aqueous solutions: saturation index, the solubility of carbon dioxide and the carbonate equilibria. The solubility of calcite. Dolomite and dolomitization.
- Redox processes: the redox potential, the Eh vs. pH diagrams of the water, Fe and Mn phases. The origin of the Mn-ore deposits. Eh vs. pH isoactivity diagrams of N, S and Cl specie.
- Silicate weathering: the stability of primary silicates and of weathering products (quartz, k-feldspar, muscovite, kaolinite, gibbsite)
- Rock weathering and mass balance calculations: variations of the mass of the chemical components and of the volume of the rocks. The Ki parameter as indicator of the mobility of the elements.
High temperature systems
- Partition coefficients: definition and dependence on temperature, pressure and composition. Compatible and incompatible behaviour of the elements. Fractionation processes: Rayleigh crystallization and total equilibrium crystallization. Melting processes: partial melting of the peridotite mantle. The geochemical diagrams (element vs. element, REE profiles, spiderdiagrams) applied to petrology.
Isotope geochemistry: the isotopes and the radioactive isotopes, the radioactive decay law. Dating: the K/Ar, Rb/Sr, U/Pb and the Pb methods.Stable isotopes: the fractionaton of the isotopes. The factors affecting fractionation. The applications of the stable isotopes to hydrological, palaeoclimatic and palaeoenvironmental studies.

Bibliography

Aquatic Chemistry - Stumm & Morgan
- Study and interpretation of the characteristics of natural waters - Hem
- Solutions, minerals and equilibria - Garrels and Christ
- Equilibres chimiques - Michard
- The geochemistry of natural waters - Drever
- Principles of isotopes geology - Faure
- Geochemistry, pathways and processes - Richardson and McSween
- Geochimica e ambiente - Dongarrà e Varrica
- Acque, minerali e ambiente - Venturelli

Teaching methods

lectures on basic theoretical topics and exercises with applications of the theoretical methods described. The teaching material is provided to the student personally or uploaded to the Elly platform after each lesson. It is part of the didactic material uploaded on Elly, a Power Point file representing the virtual whiteboard with all the annotations and graphics developed by the teacher during the lesson

Assessment methods and criteria

Oral exam with verification of theoretical knowledge, of their application to real cases and verification of logical-deductive skills (normally performed in person or remotely with the Teams platform if necessary). The grade of the oral exam (0-30) is communicated immediately at the end of the exam itself.

Other information

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